Which option is used when running smbclient with a file containing user credentials?

`-F` is not a standard `smbclient` option for credentials; it might be used for printing a fingerprint in some contexts but not for credential files.

`-c` is used to specify a command to execute directly, not a credential file.

`-s` is used to specify a `smb.conf` file to use, not a file containing credentials.

When using `smbclient`, the `-a FILE` option is used to read a username and password (or credentials in a specific format) from the specified `FILE` instead of prompting the user or reading from command-line arguments. This is useful for scripting or providing credentials securely.